Waste chrysanthemum tea derived hierarchically porous carbon for CO2 capture

Abstract

Hierarchically porous carbon (HPC) is deemed to be the most potentially useful material for CO2 adsorption due to its rich porous structure, large specific surface area, and stable chemical properties. Herein, HPC with high CO2 adsorption capacity has been prepared using waste chrysanthemum tea as a carbon precursor via simple ZnCl2 activation followed by the annealing process. N2 adsorption-desorption isotherms revealed that both the activation temperature and the ZnCl2/precursor ratio are important to form high specific surface area and abundant pores. Scanning electron microscopy images, X-ray diffraction, and Raman analysis showed that the HPC possessed a rich porous structure, attributing to amorphous carbon. Serving as an adsorbent for CO2, the HPC materials showed a maximum CO2 adsorption capacity of 3.8 mmol g−1 at 25 °C under atmospheric pressure and a remarkable reusability of 90.8% retention after 20 adsorption/regeneration cycles. Overall, the waste chrysanthemum tea derived HPC showed promising application in CO2 capture.